I would start with the speaker stands. If the horizontal planes aren't matching degrees and heights the speakers will fire at different points (angles). The right stand may be pointing it's tweeter and mid driver more directly at your ear. To effectively check I used a Husky Digital Level($36) this is key it reads out to 0.00 and something straight bridging the stands. Next I would place the speakers on the stands and check the degrees on the speaker faces. When the angles match move on to the heights of the tweeters center to center with the 8' straight edge.
Move the position of your chair forward until the imaging become to "soft" less defined. Check distance from nose to tweeter with string. Now move your chair away until you get sharper images that you like. Recheck distances with string. If the image is still to the right move your head side to side to see if this moves image towards center. If it does move chair and and mark.
Hope something here helps.
As you might be able to tell I've done some chasing/hair pulling/Hell time too.
Sam
Move the position of your chair forward until the imaging become to "soft" less defined. Check distance from nose to tweeter with string. Now move your chair away until you get sharper images that you like. Recheck distances with string. If the image is still to the right move your head side to side to see if this moves image towards center. If it does move chair and and mark.
Hope something here helps.
As you might be able to tell I've done some chasing/hair pulling/Hell time too.
Sam